The present invention relates generally to valves and more particularly, to a rotary-to-linear motion converter that is specifically adapted for proportional operation of an output shaft in response to linear movement of a cam plate.
Well known in the prior art are linear-to-rotary motion converter mechanisms that are adapted to convert linear motion of a device such as an actuator into a proportional amount of rotational motion. Such prior art linear-to-rotary motion converters may include rack and pinion mechanisms as well as various types of trunnion and clevis devices.
In addition, linear-to-rotary motion converter mechanisms are a type of control component that are used in a wide variety of applications. For example, motion converters are widely used in hydraulic and pneumatic systems in the coal, oil and gas industries. Furthermore, power plants, oil and gas refineries, and pulp and paper plants may also employ such linear-to-rotary motion converter mechanisms. As is well known, the operating environment for such applications is typically of a severe nature.
For example, certain control components that are utilized in coal, oil and gas production are typically subjected to abrasives such as dirt and grit and may be exposed to certain harmful processing materials which can infiltrate and degrade wear-sensitive components over time. Ideally, such control components must be capable of operating in a reliable manner over an extended period of time regardless of the environment.
Unfortunately, many linear-to-rotary motion converters of the prior art may be comprised of an arrangement of interconnected mechanical components such as belts, pulleys and other components that may eventually stick, bind, bend and ultimately fail over time due to the build-up of dirt, grit and oil. As can be seen, the failure of control components, such as motion converters, in severe service environments may ultimately compromise the overall operability of an entire system.
In addition, because of the configuration of such prior art motion converters, the assembly, maintenance, repair and substitution of certain parts included therewith may require a relatively high degree of technician skill. As such, prior art motion converters are understood to be undesirably complex which may contribute to relatively high assembly and operating costs. Finally, such motion converters of the prior art are typically designed to provide a specific amount of rotational motion for a given amount of linear input as may be required for a particular system. In this regard, such prior art motion converters are not understood to allow for flexibility in a variety of operating parameters.
For example, for a given system, it may be desirable to change the amount of rotational output of a motion converter for a fixed amount of linear input. Unfortunately, most motion converters of the prior art are not understood to provide such flexibility. Therefore, it may be necessary to replace the entire motion converter in order to change the relationship between linear input and rotational output for a given system to which the motion converter is installed.
As can be seen, there exists a need in the art for a linear-to-rotary motion converter that is of simple construction in order to facilitate manufacturing and maintenance thereof. Furthermore, there exists a need in the art for a motion converter that is adapted to reliably operate in severe service environments such as the environments common to the coal, oil, and gas production as well as power industries.
In this regard, there exists a need in the art for a motion converter that is capable of operating reliably in a relatively dirty environment without compromise to the overall system in which it is installed. Also, there exists a need in the art for a motion converter in which the desired amount of rotation in response to a given linear input may be readily changed. Finally, there exists a need for a motion converter that is universally adaptable to a variety of output components.